兔骨髓间充质干细胞体外分离培养条件的优化组合

背景：骨髓间充质干细胞分离培养方法的不同可导致其活性与纯度各异，直接影响组织工程的修复效果。目的：对骨髓间充质干细胞体外分离培养条件进行优化组合，并验证其获取骨髓间充质干细胞的效果。设计、时间及地点：细胞学体外实验，于2007-10/12在山西医科大学第二医院骨科实验室完成。材料：清洁级3月龄新西兰白兔2只，由山西畜牧研究所提供。方法：向含有新鲜骨髓的DMEM培养液中加入等量淋巴细胞分离液，采用密度梯度离心和差速贴壁法分离培养兔骨髓间充质干细胞，每间隔8 h将未贴壁细胞转移入新的培养瓶，接种5 d后首次换液，细胞融合率达90%时胰酶消化传代，第1、3、5代细胞用于实验。主要观察指标：镜下观察细胞形态及生长状态，绘制细胞生长曲线，测定倍增时间，流式细胞仪检测细胞表面抗原CD44标记率。结果：原代培养的骨髓间充质干细胞呈圆形、梭形、多角形等，48 h可见贴壁细胞有伸展现象，呈梭形，多角形，成纤维细胞样展开，细胞核清晰，首次换液后可见细胞透亮并充分展开，14 d左右可达90%融合。第1、3、5代骨髓间充质干细胞整体呈S型，1~3 d为潜伏期，3 d后进入对数生长期，7~8 d为平台期，平均倍增时间为24.22 h。第2代骨髓间充质干细胞CD44呈阳性表达，标记率为93.0%。结论：采用密度梯度离心联合差速贴壁、离心介质选择淋巴细胞分离液、接种5 d首次换液的体外分离培养纯化方法，获得的骨髓间充质干细胞生长状态良好，且纯度较高。

Optimization of isolation and culture conditions of rabbit bone marrow mesenchymal stem cells

BACKGROUND: Different isolation and culture methods for bone marrow mesenchymal stem cell (BMSCs) will result in varying cell activity and purity, which will influence repair effect of tissue engineering.OBJECTIVE: To investigate the optimized methods of isolation and culture of BMSCs in vitro and validate the efficacy of cell acquisition. DESIGN, TIME AND SETTING: In vitro cytology trial was performed at the laboratory of Department of Orthopedics, Second Hospital of Shanxi Medical University from October to December 2007.MATERIALS: Two 3-month-old New Zealand rabbits were provided by Shanxi Institute of Livestock. METHODS: Lymphocyte isolation solution was added to DMEM culture solution containing fresh bone marrow. BMSCs were obtained and purified by gradient centrifuge and adhesion culture in vitro. Non-attached cells were moved to new culture flask every 8 hours. The solution was changed firstly after 5 days of culture. Trypsinization was conducted at cell confluence of 90%. The first, third and fifth passages of cells were harvested. MAIN OUTCOME MEASURES: The morphology of BMSCs was observed with phase contrast microscope; the growth curve was drawn to determine doubling time. The percentage of the wel1 growth P2 cells were identified by CD44 staining by flow cytometry.RESULTS: Primary cultured BMSCs were oval, spindle-shaped or polygonal, and adhered to plastic surface within 48 hours, exhibiting spindle-shaped or polygonal with clear nucleus, and reached 90% confluence within 14 days. The first, third and fifth passages of BMSCs showed S-type, and were in latent phase at 1-3 days, in log phase 3 days later, and cells came into platform phase at 7-8 days. The mean doubling time was 24.22 hours. CD44-positive cells were found in the second passage, with positive rate of 93.0%.CONCLUSION: BMSCs are easily isolated and cultured in vitro with good growth and high purity by gradient centrifuge and adhesion culture with lymphocyte isolation solution.